The present invention is the provision of a turn signal switch assembly for heavy trucks and the like, and more particularly to a modular type turn signal switch assembly for heavy trucks having an electrical switch module, a lever housing module, and a plug module, as separately produced units which can be assembled and disassembled readily.
Heretofore, most heavy turn signals switches for trucks and the like have been constructed as an integral unit in which all of the switching, mechanical positioning, and wiring components are incorporated. In most cases, the electrical contacts are of a point contact type. These are either cam actuated or arranged to be slidable together by a rotating or linear motions supplied by a turn signal lever. Connections to the lighting system of the truck is generally accomplished by direct wiring from the handle and switch unit.
Such present switch assemblies are prone to failure due to erosion of the switch contacts caused by the heavy current load experienced on modern heavy trucks. The emergency flasher system requires a complex actuation system or a separate switch to activate all of the turn signals circuits simultaneously. The constructions of many of the present units is quite fragile, especially in regard to the construction of the handle or actuating lever. Such present system rely on a remotely located flasher to flash the lamps as required.
Repair of such prior type switches requires the removal of the switch assembly from the steering column and cleaning of the point contacts. Because this is usually not economically feasible, the switch frequently is replaced in its entirety.
An object of the present invention is to provide to the heavy trucking industry a turn signal switch construction which will have superior service life, heavy electrical load capability, lower maintenance costs, and easier repair than units presently available. This is accomplished by providing the turn signal switch as an assembly which is modular in design, providing an electrical switching unit, a mechanical unit, and a wiring unit formed as separate units.
The switch module accomplishes all required electrical switching with one rotating moving part. The contacts are designed to be self cleaning, and a set of uncommitted contacts is made available which are activated by a push button, which in turn is activated by lifting of the handle. The module is sealed, and if the switch modules should fail it may be replaced quickly without removing the lever module from the steering column. An optional flasher may be plugged directly into the switch module.
The lever housing module is of the uncomplicated rugged design, of such construction that it is possible to replace internal parts of the lever housing module without removing the module from the steering column.
The plug module connects the switch module to the lighting circuits of the truck and ensures the retention of the flasher module and switch module.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.